don't try to render troublesome tags

src/lib.rs

@@ -1,6 +1,7 @@
-use std::time::Duration;
+use std::{collections::HashMap, time::Duration};
 
 use feed_rs::parser::parse;
+use html2md::{TagHandler, TagHandlerFactory, dummy::DummyHandler};
 use reqwest::{Client, Response, StatusCode};
 use serde::{Deserialize, Serialize};
 use server::ServerState;
@@ -17,7 +18,7 @@ mod db;
 pub mod server;
 
 const ZULIP_INTERVAL: Duration = Duration::from_millis(250);
-const ZULIP_MESSAGE_CUTOFF: usize = 700;
+const ZULIP_MESSAGE_CUTOFF: usize = 500;
 
 const LAST_FETCHED: DateTime<Utc> = DateTime::from_timestamp_nanos(0);
 
@@ -187,7 +188,7 @@ impl BlogdorTheAggregator {
             let url = feed.url;
             let last_run = feed.last_run;
             let last = last_run.posted.unwrap_or(LAST_FETCHED);
-            handles.spawn(check_feed(self.client.clone(), id, url, last, feed.owner));
+            handles.spawn(check_feed(self.client(), id, url, last, feed.owner));
         }
 
         let mut feed_results = Vec::new();
@@ -562,6 +563,12 @@ async fn check_feed(
     let now = Utc::now();
     let mut feed = fetch_and_parse_feed(&url, &client).await?;
     let mut entries = Vec::new();
+    let mut handlers = HashMap::new();
+    for tag in ["a", "sub", "super", "sup", "pre"].iter() {
+        let dummy: Box<dyn TagHandlerFactory> = Box::new(Dummy);
+        handlers.insert(tag.to_string(), dummy);
+    }
+
     feed.entries.sort_by_key(|e| std::cmp::Reverse(e.posted()));
     for post in feed.entries.into_iter().take(5) {
         if post.posted().unwrap_or(LAST_FETCHED) > last_fetched {
@@ -585,7 +592,7 @@ async fn check_feed(
                 feed_description: feed.description.to_owned().map(|d| d.content),
                 body: post.content.and_then(|c| {
                     c.body.map(|f| {
-                        let s = html2md::parse_html(&f)
+                        let s = html2md::parse_html_custom(&f, &handlers)
                             .graphemes(false)
                             .take(ZULIP_MESSAGE_CUTOFF)
                             .collect::<String>();
@@ -618,5 +625,13 @@ async fn fetch_and_parse_feed(url: &str, client: &Client) -> Result<feed_rs::mod
     parse(feed.reader()).map_err(|e| format!("could not parse feed from {url}, got {e}"))
 }
 
+// so zulip doesn't choke on weird tags
+struct Dummy;
+impl TagHandlerFactory for Dummy {
+    fn instantiate(&self) -> Box<dyn TagHandler> {
+        Box::new(DummyHandler)
+    }
+}
+
 #[cfg(test)]
 mod test;